How much did Roosevelt know - The US Perspective?

Pearl Harbor has always been portrayed as a surprise attack on an unsuspecting nation. And that, to a large extent, is true. The American people's attention was focussed on the war in Europe, fearful that they would be dragged in. Already Roosevelt (Roosevelt, Franklin D.) was backing Britain against Hitler by supplying the UK with weapons under the Lend-Lease Act passed in March 1941. American shipping was in danger from attack by German submarines, the very thing that had brought America into World War I. And America had occupied Greenland and Iceland. Few Americans raised any concerns about the Sino-Japanese War which had been raging since 1937.

Whether the US administration was surprised by the attack on Pearl Harbor is another matter. A good case can be made that the US government knew of Japan's plans, or should have. There were certainly indications.

On January 27, 1941, the Peruvian envoy in Tokyo told the third secretary in the US embassy that he had learnt from intelligence sources that the Japanese had a war plan which involved an attack on Pearl Harbor. On 10 July, the US military attaché in Tokyo reported that the Japanese Navy were secretly practicing airborne torpedo attacks on targets moored in Ariake Bay-a bay that resembles Pearl Harbor. The US military attaché in Mexico also reported that the Japanese were building midget submarines which would be towed to Hawaii for an attack on Pearl Harbor.

A top British agent, codenamed 'Tricycle,' told the FBI that the Japanese planned to attack Pearl Harbor, but his information was dismissed. And a Korean agent told American broadcaster Eric Severeid that the Japanese were going to attack Pearl Harbor. The agent repeated his story to a US Senator who alerted the State Department, US Army and Navy intelligence, and President Roosevelt personally.

American intelligence had broken all the Japanese codes. On 24 September 1941, a message from Japanese Naval Intelligence headquarters in Tokyo to the Japanese consul general in Honolulu was deciphered. It requested the exact locations of all US Navy ships in Pearl Harbor. Such detailed information would only be required if the Japanese were planning an attack on the ships at their moorings. In November, another message was intercepted ordering more drills involving attacks on capital ships at anchor in preparation to 'ambush and completely destroy the US enemy.' The only American fleet within reach was at Pearl Harbor.

On 25 November, a radio message from Admiral Yamamoto (
Yamamoto, Isoruko) ordering the Japanese task force to attack the US fleet in Hawaii was intercepted. US Intelligence was understaffed and it is not known whether this message was decoded at the time. However, that same day, the US Secretary of War, Henry Stimson, noted in his diary:

'FDR stated that we were likely to be attacked perhaps as soon as next Monday. FDR asked: 'The question was how we should maneuver them into the position of firing the first shot without too much danger to ourselves. In spite of the risk involved, however, in letting the Japanese fire the first shot, we realized that in order to have the full support of the American people it was desirable to make sure that the Japanese be the ones to do this so that there should remain no doubt in anyone's mind as to who were the aggressors.''

On 29 November, US Secretary of State Cordell Hull (Hull, Cordell) showed a reporter from The New York Times a message saying that Pearl Harbor was going to be attacked on 7 December. As the attack approached, the American government received information from numerous sources that 7 December would be the day. On 1 December, Naval Intelligence in San Francisco worked out from news reports and signals picked up by shipping companies that the Japanese fleet that had disappeared from home waters was then to the west of Hawaii. Those who believe that Roosevelt knew about the attack all along maintain that a number of other reports say that the Japanese would strike at Pearl Harbor, but they have yet to be declassified.

With hindsight, it is clear that the information that showed the Japanese would attack at Pearl Harbor was there. But it is a very serious matter to say that President Roosevelt knew where and when the attack would come and did nothing about it. It is, essentially, accusing him of treason. However, the Japanese attack did suit his purposes well. Since the fall of France in June 1940, Roosevelt had believed that America would have to go to war against Hitler. In August 1941, when Roosevelt and Churchill met on warships in the Atlantic, Churchill noted the 'astonishing depth of Roosevelt's intense desire for war.' But the American people had no wish to get involved in a European war. Even Roosevelt conceded that 'the American people would never agree to enter the war in Europe unless they were attacked within their own borders.'

Roosevelt was right. After the attack on Pearl Harbor, the American people were willing, if not eager, to go to war. Once the US had declared war on Japan, under the provisions of the Tripartite Pact signed by Germany, Italy, and Japan on September 1940, Hitler declared war on the US. At the Atlantic Conference, Roosevelt had already agreed with Churchill that the priority was to defeat Hitler, before finishing off Japan. So the attack on Pearl Harbor allowed Roosevelt to get America into the war against Germany 'through the back door.' It is difficult to see how else this could have been achieved and there are those who contend that Roosevelt's plan to get America into the war against the wishes of its people was the 'mother of all conspiracies.' They maintain that Roosevelt moved the Pacific fleet from the West Coast out to Hawaii against the advice of his commanders, not to threaten the Japanese, but as bait.

Admiral Richardson (Richardson, James O.) complained that Pearl Harbor had inadequate air defenses and no defense against torpedo attack, as did his successor Admiral Kimmel (Kimmel, Husband E.). And when the aircraft carriers were ordered out of Pearl Harbor, it further deprived Pearl of air defenses at a time when Roosevelt's negotiations with the Japanese were at their most provocative.

The conspiracy theorists say that the attack was stage managed to make America look weak. If America had looked strong and well-prepared, Germany might not have declared war. While this theory is plausible, the conspiracy theorists go further. They maintain that Roosevelt was a secret admirer of the Soviet Union and wanted to fight Germany to defend Russia, but could never expect to get the American people to ally themselves directly with the Soviets. According to this theory, Roosevelt also conspired with Stalin to use the war to destabilize the British Empire. In such a grand scheme, the sacrifice of a few thousand American lives at Pearl Harbor was small beer.The attack on Pearl Harbor was played up by the government and the press as the most infamous act in history, though it was known that the Japanese never declared war before attacking. Some 2,403 people were killed at Pearl Harbor and 1,178 wounded. However, these casualties are slight compared to later losses in the war. The US aircraft carriers were unscathed and only two capital ships lost completely.

While it is true that various wings of the US government did have good reason to suspect that the attack would come at Pearl Harbor, it is difficult to know now how far this intelligence was transmitted. With the nation not yet at war, there were often delays in sending incepted message for decryption. US Intelligence was short staffed and there were long delays in decoding and reading even high priority traffic. Some incepts were filed and forgotten, and it is not possible to know how much President Roosevelt and other key players knew at the time. For example, due to concern that the Japanese might realize their codes had been broken, President Roosevelt himself was taken off the list of raw intelligence sent between 20 May and 12 November, 1941. During that period he was only given an oral summary.

It was noted at the time that Roosevelt, usually a highly strung man, was surprisingly calm on the night of 7 December, 1941, as if a great weight had been lifted from his shoulders. America was now at war.